Stream Periphytic Biodegradation of the Anionic Surfactant C sub(12)-Alkyl Sulfate at Environmentally Relevant Concentrations

Stream mesocosms were subjected to contamination various concentrations of alkyl sulfate anionic surfactants, and the effects on the periphytic microbes was monitored for eight weeks. For streams dosed with at least 61 mu g/l, turnover rates increased significantly, although the temperature dropped 10 degree C during the period. Turnover rate correlated with surfactant concentration. During the monitoring period, bacterial density increased, but biomass was not related to acclimation of the bacteria to biodegrade the surfactant. An increase in bacterial activity was unrelated to density or biodegradation. The high dose stream, which was contaminate with concentrations that were two orders of magnitude above environmentally relevant concentrations, demonstrated a shift in the bacterial community. At concentrations that are usually found in the environment, the bacterial community was able to rapidly acclimate to the surfactant and degrade it.